The invention relates to an axial fan with blades that automatically adjust to the direction of rotation. The blades are mounted so they can swivel freely on the fan wheel with their swiveling action being limited by stops provided on the fan wheel.
A typical axial fan is disclosed by published German patent application DE-OS No. 2736773. In order to obtain the advantages of an axial fan for machines that can reverse their direction of rotation, the individual blades used in the fan are mounted with freedom to swivel, by means of a separate pivot pin. When the direction of rotation is reversed, the fan blades swivel automatically into the other final position, as a result of both their inertia and the air resistance so that even when the direction of rotation is reversed, the air continues to be moved in the same direction. The swivel arrangement, however, results in high manufacturing costs, beacause every fan blade must be individually mounted.